• 한국정밀공학회지
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• 제31권3호
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• pp.181-187
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• 2014

Micro patterns are used to maximize the performance and efficiency of the product in many industries such as energy, display, printing, biology, etc. Nowadays, the fabrication technology for micro patterns has been developed in various ways such as photolithography, laser machining, electrical discharge machining and mechanical machining. Recently, mechanical machining the size of smaller than 1 micrometer could be tried, because the technology related to the machining was developed brilliantly. This paper shows the experiments using cutting processes in order to fabricate the micro pattern. Micro patterns of the size of several micrometers were machined by the diamond tools of two different shape, the deformation and generation of burr were investigated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.593-597
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• 2005

FIB equipment can perform sputtering and chemical vapor deposition simultaneously. It is very advantageously used to fabricate a micro structure part having 3D shape because the minimum beam size of ${\phi}$ 10nm and smaller is available. Currently FIB is not being applied in the fabrication of this micro part because of some problems to redeposition and charging effect of the substrate causing reduction of accuracy with regards to shape and productivity. Furthermore, the prediction of the material removal rate information should be required but it has been insufficient for micro part fabrication. The paper have the targets that are FIB-CVD characteristic analysis and minimum line pattern resolution achievement fur 3D micro fabrication. We make conclusions with the analysis of the results of the experiment according to beam current, pattern size and scanning parameters. CVD of 8 pico ampere shows superior CVD yield but CVD of 1318 pico ampere shows the pattern sputtered. And dwell time is dominant parameter relating to CVD yield.

• 한국정밀공학회지
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• 제21권6호
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• pp.35-42
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• 2004

At the large-sized mold fer injection molding, the remaining gas in the mold causes some problems with final products. In order to solve these problems, air-bent was drilled on the surface of mold. However, this method leaves the scar on the surface of a product. Therefore, porous material was developed to the removal of remaining gas in this study. Porcerax II, which is a commercialized porous material, were developed in USA. It requires the electric discharge machining(EDM) process to make pores on the surface of the materials. The electric discharge machining (EDM) process, however, cause the increase of the time and cost for the fabrication of the mold. In this study, high speed machining(HSM) process was applied to the fabrication of porous mold without electric discharge machining(EDM) process. Some characteristics of the developed materials machined by high speed machining(HSM) and electric discharge machining(EDM) including air-permeability and porosity were compared with those of Porcerax II. Besides, in order to be applied to the molding process, hardness and tensile ＆ yield strength were compared between Porcerax II and developed materials.

• 한국의사학회지
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• 제25권2호
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• pp.137-153
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• 2012

A thesis insisting that Sugjong's medical doctor Yoo Itae(劉以泰) and the author of Marjinpyeon Yoo Itae(劉爾泰) are not a same person and his activities were in Heonjong(헌종) period, and his writing Marjinpyeon is in 1846, is published. In this study, I'd like to reveal that Yoo Itae(劉爾泰), the Marjinpyeon's author and Yoo Itae(劉以泰), Sugjong's medical doctor are a same person through analysis of Geochang Yoo's genealogy, articles, The True Record of the Joseon Dynasty, Seungjeonilgi, Taeweonseonsaengan, Sancheong-gun's paper, Sancheong Hyanggyo's paper, Sancheong-gun's paper, The geographic paper, Dongyuhagan, Sawoo Munjib, and analysis of folk story, the wrote year of his Marjinpyeon and Inseomunkyunrok and his birth year. According to my analysis, Yoo Itae(劉爾泰), the Marjinpyeon's author and Yoo Itae(劉以泰), Sugjong's medical doctor are a same person. And Marjinpyeon is written in 1696, the year of Byongja, and other his books, InseoMungyonlok at 1709, the year of Gichug. In conclusion, Yoo Itae(劉以泰.劉爾泰) was a famous medical doctor at Sancheong, born in 1652 (HyoJong the $3^{rd}$ year) and passed in 1715 (SugJong the 41th year), left books of Marjinpyeon, Silheomdanbang, and Inseomunkyunrok.

• 한국지역지리학회지
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• 제18권1호
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• pp.27-41
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• 2012

이 연구에서는 여백에 무수한 교정과 첨가의 흔적이 담겨 있는 국립중앙도서관 소장 "동여편고"의 내용을 정리 소개하고, 지리지 편찬 역사에서 차지하는 학술적 가치를 살펴보고자 하였다. 결과를 요약하면 첫째, "동여편고"는 순조(재위: 1800~1834) 때 "신증동국여지승람"에서 유래 관련 내용을 대폭 삭제하여 편찬되었다. 둘째, 주로 순조 때 "동국문헌비고"의 정보를 중심으로 교정과 첨가 작업을 진행하였다. 셋째, 헌종(재위: 1834~1849) 때도 "중정남한지"등 여러 자료를 바탕으로 교정과 첨가 작업을 진행하였다. 넷째, 양주의 읍치 이동에 대한 기록과 지리지 전체의 편찬경향을 통해 볼 때 "동여편고"의 편찬자는 김정호이다. "동여편고"는 우리나라의 가장 위대한 지리학자인 김정호 인생의 초기에 진행된 지리지 편찬 과정을 생생하게 담고 있는 중요한 자료로서, 그 동안 자료의 부족으로 주목하지 못했던 1834년 이전의 김정호 삶을 이해할 수 있게 해주는 학술적 가치를 갖고 있다.

• 한국정밀공학회지
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• 제17권10호
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• pp.155-161
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• 2000

Recently, environmental pollution has become a big problem in industry and many researches have been done in order to preserve the environment. In the grinding process, the coolant has great influence on environment. It contains several chemicals(sulfur, phosphorus and chlorine) to improve the grinding efficiency. If these additives go into the workplace atmosphere, it is harmful for workers. It can also cause the environment pollution. Because of these reasons many studies have been done to minimize the amount of coolant. However the small amount of coolant can cause the thermal defect on the ground surface layer. This study forced the effects of the compressed cold air when the spindle shaft materials(SCM4 & SCM21) were cylindrical ground with WA wheel. The compressed cold air was used as the coolant and grinding performance was compared with that of the conventional grinding fluids(emulsion). Many experiments were carried out with these two cooling materials. The surface roughness, residual stress, and roundness were measured for the cylindrical grinding. The test results showed that the compressed cold air was very useful as the cooling materials for grinding process. It was also efficient to minimize the thermal defects of workpiece and could also play a role in solving environmental pollution.

• 고문화
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• 63호
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• pp.65-82
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• 2004

우리나라 후기구석기시대의 가장 전형적인 문화기는 돌날석기문화와 세형돌날문화와 연관이 있다. 최근 고례리유적과 진그늘유적의 발견으로 우리나라의 전형적인 돌날석기문화가 있음이 확인되었다. 세형돌날 문화는 동북아시아의 25,000년전에 시작된 아시아적인 소형화개넘(microlism)의 전형으로서 동북아시아의 석기문화가 통합되는 계기를 만들었으며 우리나라의 전역에 널리 퍼져있는 대표적인 문화기이다. 이러한 후기구석기시대의 일련의 유적들은 크게 돌날기법과 연관이 있으며, 우리나라 후기구석기시대의 몸돌 성형과 박리기법 등 기술적인 측면에서의 문화 맥락적인 연계성을 확인할 필요가 있다 자갈돌석기전통의 다층위유적 가운데 후기구석기시대 문화층으로 보고된 유적과 절대연대 상 40,000-25,000년 전의 후기구석기시대 유적들에서 확인되는 측면몸돌은 기술적 측면에서 전형적인 돌날석기문화와의 상관관계속에서 나타나는 다양한 문화적 변이를 설명해 주고 있다. 이 몸돌은 시베리아와 극동지역의 후기구석기시대에 자주 출토되는 대표적인 몸돌 중 하나이다. 측면몸돌은 몸돌의 좁은 측면에서 많은 돌날을 떼어내고 재생을 하기에도 용이한 기술적 특징을 갖고 있으며 석재의 제약을 비교적 털 받는 전략적인 몸돌이었다. 우리나리에서 출토되는 측면몸돌은 돌날기법과 연관이 있으며 후기구석기시대로 진입하는 단계에 동북아시아에 정착해 가던 돌날석기문화와의 기술적인 교류의 한 단면을 보여주는 것이라고 생각된다. 이러한 기술적 기반을 갖고 있던 한반도에 점거하며 살던 구석기시대 사람들은 돌날석기문화와 세형돌날문화가 등장하는 시기마다 적응 해 갈 수 있었을 것이며, 다양한 돌날몸돌을 다를 때 측면몸돌을 제작하던 기술로 인한 적응력도 높여 갈 수 있었을 것으로 보인다. 특히 우리나라의 후기구석기시대의 이른 단계로 편년되는 자갈돌석기전통의 유적들에서 이러한 몸돌들이 함께 나라나는 것은 후기구석기시대의 자갈돌석기전통의 연속성에 대한 또 하나의 증거이며 지역적인 적응의 결과의 하나로 볼 수 있다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.187-192
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• 2006

In the absence of a clear command and control structure, a key challenge in supply chain management is the coordination and alignment of the supply chain members who pursue divergent and often conflicting goals. The newsvendor model is typically used as a framework to quantify the cost of misalignment and to assess the impact of coordination initiatives. This paper considers a fuzzy approach for the newsvendor problem which includes a single manufacturer and a single retailer. We use several fuzzy parameters in the model such as the demand, the wholesale price, and the market sales price. We apply a coordination policy, referred to as buyback, to solve the fuzzy newsvendor problem. Based on the buyback policy, the optimal order quantity of the retailer can be computed, and the possible profits of the members in the supply chain can be calculated with minimum sharing of private information. Focusing on the fuzzy model with buyback policy for the newsvendor problem, we illustrate exemplary fuzzy models. We also illustrate an integration model, which extends a single-manufacturer-single-retailer model to the single-manufacturer-multiple-retailer setting. In the extended model, we consider three coordination policies including quantity discount, profit sharing, and buyback, as well as non-coordination case.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.158-161
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• 2003

Recently, the evolution in production techniques (e.g. high-speed milling), the complex shapes involved in modem production design, and the ever increasing pressure for higher productivity demand a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. And also machine tools of multi functional and minimized parts are increasingly required as demand of higher accurate in some fields such as electronic and optical components etc. The accuracy and the productivity of machined parts are natural to depend on the linear system of machine tools. The complex workpiece surfaces encountered in present-day products and generated by CAD systems are to be transformed into tool paths for machine tools. The more complex these tool paths and the higher the speed requirements, the higher the acceleration requirements are needed to the machine tool axes and the motion control system, and the more difficult it is to meet the requirements. The traditional indirect drive design for high speed machine tools, which consists of a rotary motor with a ball-screw transmission to the slide, is limited in speed, acceleration, and accuracy. The direct drive design of machine tool axes. which is based on linear motors and which recently appeared on the market. is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, no mechanical limitations on acceleration and velocity and mechanical simplicity. Therefore performance tests were carried out to machine tool axes based on linear motor. Especially, dynamic characteristics were investigated through circular test.

• 한국정밀공학회지
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• 제30권11호
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• pp.1121-1128
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• 2013

Ultrasonic grinding system is that the ultrasonic vibration by ultrasonic actuator is applied on conventional grinding system during grinding process. The Ultrasonic vibration with a frequency of over 20kHz can reduce grinding forces and increase surface quality, material removal rate (MRR) and grinding wheel life. In addition, ultrasonic vibration assisted grinding can be used for the materials that are difficult to cut. In this paper, methodology for ultrasonic tools is studied based on finite element method, and in turn the ultrasonic tools are designed and fabricated. It is found that the ultrasonic tool can vibrate with a frequency of 20kHz and amplitude of $25{\mu}m$. In order to verify the machining performance, the grinding experiment is performed on titanium alloy. By applying ultrasonic vibration, the grinding force and temperature are reduced and MRR is increased compared with the conventional grinding.